The present invention relates to a monitoring and control system for sensing the presence and/or absence of a vessel on a cooktop and other properties of the cooktop, and more specifically, the present invention relates to sensing various properties of a cooktop independent of the reflectivity of the vessel to gather the information.
In some conventional cooktops or ranges, the reflective properties of a vessel positioned on the surface of the cooktop are used to determine states and/or other properties of the cooktop, vessel or cooking process. However, the reflective properties vary between vessels. In addition, with age and usage of the vessel, the reflective properties of the vessel can diminish due to for example corrosion, staining and burned on coatings. Thus, the use of vessel reflective properties to determine the states and/or other properties of the cooktop, vessel or cooking process may, at times, be unreliable or inconsistent. Therefore, it is desired to have a cooktop and/or range that uses a system that is not dependent upon the reflective properties of the vessel when determining states and/or characteristics of the cooktop, vessel or cooking process.
As described above, in some conventional cooktops or ranges, the determination of the states and/or other properties of the cooktop, vessel or cooking process can be dependent upon the signals that are reflected from the vessel and detected by the sensor. As such, the reflectivity of the vessel is directly related to the amount of reflected signals that are detected by the sensor. Therefore, a decrease in the reflective properties of the vessel decreases the amount of reflected signals and, thus, directly affects the determination of the states and/or other properties of the cooktop, vessel or the cooking process. For example, the presence of a vessel on the cooktop can be detected when a greater amount of signals are reflected and/or detected as compared to the amount of signals reflected and/or detected when the vessel is not present on the cooktop. In one example, a vessel having very poor reflective qualities can be placed on the cooktop and the sensor system of the cooktop and/or range may not be able to determine if the vessel is present on the cooktop due to the poor reflective qualities of the vessel.
So that problems associated with overheating the cooktop surface are avoided, some modern cooktop and/or range controllers are programmed to heat the cooktop or range only when a vessel is present. When a cooktop or range sensor system is unable to detect the presence of a vessel having poor reflective properties, a user may become dissatisfied when the cooktop or range does not heat when the vessel is placed on the cooktop. The user may be further dissatisfied when an old vessel must be replaced with a new vessel having better reflective properties. Thus, it is desired to have a cooktop and/or range that detects the presence, absence or other properties of a vessel on the cooktop that is independent from the reflective properties of the vessel.
In one exemplary embodiment, an apparatus for determining properties of a cooktop is provided. The cooktop includes a cooktop surface and a vessel selectively placed on the cooktop surface. The apparatus comprises a radiation source positioned below the cooktop surface. The radiation source generates radiation and transmits the radiation through the cooktop surface to a position above the cooktop surface. A reflective surface is positioned above the cooktop surface and reflects at least a portion of the transmitted radiation. A radiation sensor is positioned below the cooktop surface and sensing at least a portion of the reflected radiation that passes through the cooktop surface. The radiation sensor also generates a detected radiation signal in response to the sensed radiation. A processor is connected to the radiation sensor and receives the detected radiation signal, and the processor determines properties of the cooktop from analyzing the detected radiation signal.
In another exemplary embodiment, a method for detecting properties of a cooktop is provided. The cooktop includes a cooktop surface and a vessel selectively placed on the cooktop surface. The method comprises the steps of generating radiation at a position below the cooktop surface. The generated radiation is transmitted through the cooktop surface to a position above the cooktop surface. At least a portion of the transmitted radiation is reflected toward the cooktop surface using a reflective member. A portion of the reflected radiation passing through the cooktop surface is detected. Properties of the cooktop are determined from the detected radiation.